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Aqualung Legend LX O-ring Shore A Hardness / Duro

Discussion in 'Aqua Lung' started by Peter Vegas, May 31, 2019.

  1. Peter Vegas

    Peter Vegas Angel Fish

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    Hello,
    I'm trying to find out o-ring Shore A / Duro hardness for Aqualung Legend LX (present) model as I'm not able to purchase it from any dealer.
    The o-ring is a standard overhaul part 820009P as seen in the image below (Item 28).
    This o-ring shows up in older (2011) service manual as 473056 O-ring 1.78x5.28 EPDM 80ShA.
    Can anyone confirm that the current 820009P o-ring is also EPDM with hardness of 80 Shore A?
    Thank you.

    full.jpg
     
  2. Zef

    Zef Divemaster

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    The HP port (part # 46 in the diagram) should take a 90 shore o-ring.
    The MP port (part # 44) should take a 70 shore o-ring.
    I am pretty sure that part # 28 should be a 90 shore o-ring as it receives high pressure at the cylinder valve - 1st stage ACD interface.

    80 shore is a happy medium between 70 and 90...70 is typically used for LP/MP applications and 90 is typically used for HP applications to prevent the o-ring extruding out of position under the high pressure.

    -Z
     
  3. Peter Vegas

    Peter Vegas Angel Fish

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    Hey Z. Thank you for your response. Looks like Part # 24, is also used with ACD (yoke) and filter. This area would also be under high pressure. Therefore requiring 90 shore also. Would you agree?
     
  4. Zef

    Zef Divemaster

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    Short answer: Yes, I agree.

    Long Answer:
    You can use 90 shore every where o-ring part #24 is specified in the diagram...you dont need a to use a 70 shore o-ring on the mp port plug unless you really want to have 2 versions of the same o-ring....the mp port plug does not need 90 shore, per se, but it won't be a problem there either. Where a harder o-ring could be problematic is in an application wherethe o-ring moves and a softer o-ring is specifically specified...this is called a dynamic application....because the mp port o-ring is static once the port plug is installed and the o-ring is captive, there should be no problem with the harder composition.

    -Z
     

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